Originally Posted by BUFFALO
Thanks for the replys.
Sounds like I'm not too far off base with trying up to 3 more degrees.
Forgot to mention it earlier. There are some shims under the leaf pack that look like they are caster shims. I would guess adding some there wouldn't be the best idea and doing the sleeves would be a better idea? Or maybe remove the shims that are there and replace with a single wedge that provides more caster would also be acceptable?
Yeah, I'd shoot for 5-5.5. Even a little more is ok for steering precision, but it can increase steering effort at the extremes.
Here's a good write up on using shims:
Drivelines & Geometry: Understanding Pinion And Driveshaft Angle - Four Wheeler Magazine
Basically, shims can be used for adjusting caster, but it will change the driveline angle too. If the two need to move in opposite directions, that's when the ball-joint sleeves should be used instead. Also, leaf springs change caster as they sag, so something to keep in mind.
I know Ford does allow stacking shims in the heavy duty trucks, but I'm not sure what their policy is on a driven front axle. I don't really see it any different from adding leafs, but the Four Wheelers guys recommend not going past 6-degrees with shims.